Seeking New Way to Detect Myocardial Ischemia

Images produced by the new MRI technique being developed at Cedars-Sinai show defects in coronary blood flow in a patient with suspected coronary artery disease. In the top row, arrows indicate blood flow defects in three sections; in the bottom row, arrows indicate the corresponding narrowing of two coronary arteries.

Cedars-Sinai scientists have received a four-year, $3.3 million grant from the National Institutes of Health for a project aimed at developing a noninvasive, radiation-free MRI technique to detect myocardial ischemia — a reduction in blood flow that can lead to a heart attack.

Early diagnosis of myocardial ischemia, which commonly results from coronary artery disease, can facilitate medical interventions that may lower rates of heart injury and death, according to the study's principal investigator, Debiao Li, PhD, director of the Cedars-Sinai Biomedical Imaging Research Institute (BIRI) and professor of Biomedical Sciences and Imaging. Coronary artery disease is the most frequent cause of death worldwide for both men and women.

The ability to diagnose myocardial ischemia is limited by the imaging technologies most commonly used for this purpose — single-photon emission computerized tomography (SPECT) and positron emission tomography (PET). SPECT has low spatial resolution, and PET is not widely used due to limited availability and high costs, explained Daniel S. Berman, MD, co-investigator for the study. Berman is chief of Cardiac Imaging and Nuclear Cardiology at the Cedars-Sinai Heart Institute and the S. Mark Taper Foundation Imaging Center, medical director of BIRI and professor of Imaging.

Behzad Sharif, PhD, another co-investigator for the study and assistant professor of Biomedical Sciences, said he believes that the novel MRI technique the team is developing may provide a better alternative to SPECT and PET by accurately and reliably measuring blood flow across all layers and regions of the heart muscle.

"This is significant because nearly half of stable patients who experience chest pain or discomfort who undergo invasive testing are found to have no obstructive coronary artery disease. The technique we are developing could potentially lead to considerable cost savings and improved treatment for patients," Li explained.

Debiao Li, PhD

C. Noel Bairey Merz, MD, also a co-investigator for the study, said she hopes the new technique may one day serve to accurately identify patients who are most likely to benefit from invasive procedures that restore blood flow to the heart, such as coronary stents or bypass surgery, versus those who can benefit from medical therapies alone. Bairey Merz is director of the Barbra Streisand Women's Heart Center, director of the Preventive and Rehabilitative Cardiac Center at the Heart Institute and professor of Medicine.

In addition to Cedars-Sinai researchers, the project involves electrical and computer engineering professors Zhi-Pei Liang, PhD, and Yoram Bresler, PhD, from the University of Illinois at Urbana-Champaign.